I got my first Mcintosh yesterday. Hooked it up and sounded great with Trio preamp into a Eminence Commonwealth. Shut it down to change over to the 4ohm tap for a 212 K120 cab and upon power up loud hum and blown fuse. New fuse, tried again, same hum and blown fuse. Thought it might be the 4ohm tap so I hooked it back up to the 8ohm 112 cab same. Took it into the Kansas City Mac tech and he said it sounds like a transformer and I am screwed. It will take a week or so before the tech does a diagonstic on it so I am remaining optimistic. But I think I killed my Mcintosh.

Sorry to hear this bad news. I doubt you killed it, assuming you connected everything right. They're hard to kill due to all the protective measures they have built in. Sounds like a stroke of bad luck and something that was going to go on its own. Where did you get it from? I have an MC50 and an MC2120 and the only thing I've ever done to either is adjust the bias on the 2120 because one channel was running too hot. I've been thrashing on both of them for years with out a problem. Good luck and keep us posted.

This is odd because I just scored a mc50 on eBay for $260, fully functional, but in poor cosmetic condition (could care less), and I was just coming on here to post my excitement. Anyways, even if it is the transformer, can that not be replaced? It will work out man. It always does! Keep us posted.

Thanks guys for the well wishes. I will let you know what happens. The tech said the trannies on the old stuff before 76? you cant get replacements for. He was just preparing me for the worst but it could be just a cap or something easy.

Searing75 wrote:This is odd because I just scored a mc50 on eBay for $260, fully functional, but in poor cosmetic condition (could care less), and I was just coming on here to post my excitement. Anyways, even if it is the transformer, can that not be replaced? It will work out man. It always does! Keep us posted.

Chris

Those transformers are not replaceable. I suppose you might be able to find a place to rewind it, but it would cost more than it would to get another amp.

That said, they rarely blow. Mac transformers are way overbuilt and these amps can take insane abuse.

Yeah. I replaced all of the caps in mine, and the transistors, and diodes. I may also change the resistors, but they are all within spec. It sounds wonderful! Replacing the big cans seemed to improve the tone most.

Thanks Chris. I will ask the tech about the big cans. Did you replace the RCA or speaker jacks with 1/4"? The hifi guys at the shop turned and looked at me like I was an ahole when I asked about changing the jacks. They already accused me of killing a mac by plugging a guitar into it.

I did. For the input and output. I did the big caps and the transistors at the same time, so I can't point my finger to what really improved the tone and tightness. Get yourself a soldering iron, and start to teach yourself this stuff. You will be so happy that you did!